Ablative Mechanical Fastener

Abstract

A mechanical fastener is provided for securing an ablative material of finite thickness to a metallic substrate, said ablative material subjected to high temperature erosion on a proximal side to protect said substrate on a distal side. The fastener includes a flathead bolt and a nut. The bolt includes a conical head and an externally threaded shaft. The head has a height substantially equal to the thickness of the ablative material and a taper angle between 45° and 60°. The bolt is insertable through the ablative material from the proximal side, with the shaft extending through the substrate on the distal side. The nut mates the bolt with the substrate from the distal side. The nut has an internal thread that interfaces with the shaft. The bolt is composed of a material able to withstand the high temperature erosion.

What is claimed is: 
     
         1 . A mechanical fastener for securing an ablative material of finite thickness to a metallic substrate, said ablative material subjected to high temperature erosion on a proximal side to protect said substrate on a distal side, said fastener comprising:
 a flathead bolt that includes a conical head and an externally threaded shaft, said head having a height substantially equal to the thickness of the ablative material and a taper angle between 45° and 60°, said bolt being insertable through the ablative material from the proximal side, with said shaft extending through the substrate on the distal side; and   a nut that mates said bolt with the substrate from the distal side, said nut having an internal thread that interfaces with said shaft, wherein said bolt is composed of a material able to withstand the high temperature erosion.   
     
     
         2 . The fastener according to  claim 1 , further including a washer disposed between said nut and the substrate. 
     
     
         3 . The fastener according to  claim 1 , wherein said nut is capped as an acorn nut, which is welded to the substrate. 
     
     
         4 . The fastener according to  claim 1 , wherein said head further includes a hexagonal cavity for receiving an Allen wrench. 
     
     
         5 . The fastener according to  claim 1 , wherein said bolt is composed from one of stainless steel, carbon steel, molybdenum and tungsten alloy.